Student1: so if you increase one you have to decrease the other to make it multiply to 250.
Teacher : What did you do to the radius to get the base area?
Student: Pi-r-squared... ?
Teacher : What did you do to the radius to get the base area?
Student1: It's, ah, pi-r-squared, so you...
Teacher : Pi-r-squared. I want you to think about the x-axis. As the radius goes up by one,
Teacher : think about radius squared. The radius is one, what's r-squared?
Student: One
Teacher : One. If the radius is 2, what's r-squared?
Student: 4
Teacher : 4. So it jumped by...
Student: 3.
Teacher : If the radius goes up to 3, what's r-squared?
Student: 9.
Teacher: 9. So it jumped by...
Student: 6.
Teacher : 5. So as your radius goes up by 1, your height is changing
Teacher : because you're squaring the radius. We haven't really had a problem like that before.
Teacher : But your radius is getting squared, isn't it?
Teacher : And so it isn't changing by a constant amount, it's squared.
Teacher : But just to correct you, on the x-axis, is the radius going up by a constant amount?
Student: Yes.
Teacher : Yes. The radius goes up by a constant amount...
Teacher : Yes. The radius goes up by a constant amount...
Teacher : Yes. The radius goes up by a constant amount...
Student1: But the base area isn't.
Teacher : Right. Because of the squaring... Okay, good. Okay, number three,
Teacher : Right. Because of the squaring... Okay, good.